Method for regulating fluid pump pressure

Abstract

A method is provided for regulating fluid pump pressures by detecting an elevation differential between a fluid flow control device and the distal end of a fluid line in communication with the fluid flow control device. A fluid flow control device, for instance a peritoneal dialysis device, is at a first height, a distal end of a fluid line is at a second height, and a valved outlet, when open, affords communication between the fluid flow control device and the distal end of the fluid line. The elevation differential is correlatable with a pressure measurable during a calibration procedure provided as a part of the methodology.

What is claimed is:  
     
       1. A method for regulating pressure at a distal end of a fluid line, the method comprising: 
       providing a fluid flow control system, the fluid flow control system having at least one liquid volume in valved communication with. the distal end, a control volume in pressure communication with the liquid volume, means for measuring pressure in the control volume, and means for adjusting the pressure in the control volume;  
       calibrating the means for measuring the pressure;  
       establishing communication between the liquid volume and the distal end;  
       measuring a pressure of the control volume; and  
       adjusting the pressure in the control volume in accordance with the measured pressure.  
     
     
       2. A method according to  claim 1 , wherein the liquid volume includes a flexible membrane that separates the liquid volume from the control volume. 
     
     
       3. A method according to  claim 1 , wherein the fluid flow control system includes a pump. 
     
     
       4. A method for regulating pressure in a fluid line, the method comprising: 
       providing a fluid flow control system, the fluid flow control system having at least one liquid volume in valved communication with a distal end of a fluid line;  
       isolating the liquid volume from the distal end;  
       measuring a first calibration pressure of a control volume in pressure communication with the liquid volume;  
       pressurizing the liquid volume;  
       measuring a second calibration pressure of the control volume;  
       establishing communication between the liquid volume and the distal end;  
       measuring a pressure of the control volume; and  
       adjusting the pressure in accordance with the measured pressure and the first and second calibration pressures.  
     
     
       5. A method according to  claim 4 , wherein the liquid volume includes a flexible membrane that separates the liquid volume from the control volume. 
     
     
       6. A method according to  claim 4 , wherein the fluid flow control system includes a pump. 
     
     
       7. A method for regulating pressure in a fluid line, the method comprising: 
       providing a fluid flow control system, the fluid flow control system having at least one liquid volume in valved communication with a distal end of a fluid line;  
       isolating the liquid volume from the distal end;  
       measuring the pressure of a control volume in pressure communication with the liquid volume;  
       positively pressurizing the liquid volume;  
       measuring the pressure of the control volume while the liquid volume is positively pressurized;  
       negatively pressurizing the liquid volume;  
       measuring a pressure of the control volume while the liquid volume is negatively pressurized;  
       establishing communication between the liquid volume and the distal end;  
       measuring the pressure of the control volume; and  
       adjusting the pressure in accordance with the measured pressure.  
     
     
       8. A method according to  claim 7 , wherein the liquid volume includes a flexible membrane that separates the liquid volume from the control volume. 
     
     
       9. A method according to  claim 7 , wherein the fluid flow control system includes a pump. 
     
     
       10. A method for regulating pressure in a fluid line, the method comprising: 
       providing a fluid flow control system, the fluid flow control system having means for measuring pressure, a first liquid volume and a second liquid volume, the first liquid volume in valved communication with the second liquid volume;  
       establishing valved communication between a distal end of the fluid line and the first liquid volume and the second liquid volume;  
       calibrating the means for measuring pressure;  
       establishing communication between the first liquid volume and the distal end;  
       measuring a pressure of a fluid in pressure equilibrium with liquid in the first liquid volume;  
       adjusting the pressure in accordance with the measured pressure.  
     
     
       11. A method according to  claim 10 , wherein calibrating the means for measuring pressure comprises: 
       isolating the liquid volumes from the distal end;  
       measuring a first calibration pressure of the fluid in pressure equilibrium with liquid in the first liquid volume and a first calibration pressure of a fluid in pressure equilibrium with liquid in the second liquid volume;  
       pressurizing the first liquid volume;  
       measuring a second calibration pressure of the fluid in pressure equilibrium with liquid in the second liquid volume; and  
       adjusting the pressure in accordance with the measured pressures.  
     
     
       12. A method according to  claim 10 , wherein calibrating the means for measuring pressure comprises: 
       isolating the liquid volumes from the distal end;  
       measuring a first calibration pressure of the fluid in pressure equilibrium with liquid in the first liquid volume and a first calibration pressure of a fluid in pressure equilibrium with liquid in the second liquid volume;  
       positively pressurizing the first liquid volume;  
       measuring a second calibration pressure of the fluid in pressure equilibrium with liquid in the second liquid volume while the first liquid volume is positively pressurized;  
       negatively pressurizing the first liquid volume;  
       measuring a third calibration pressure of the fluid in pressure equilibrium with liquid in the second liquid volume while the first liquid volume is negatively pressurized; and  
       adjusting the pressure in accordance with the measured pressures.  
     
     
       13. A method according to  claim 10 , wherein each of the first and second liquid volumes includes a flexible membrane that separates the liquid volume from a control volume, and wherein the pressure measurements are taken from the control volume. 
     
     
       14. A method according to  claim 10 , wherein the first and second liquid volumes are disposed within a cassette. 
     
     
       15. A method according to  claim 14 , wherein the fluid flow control system includes a pump. 
     
     
       16. A method for regulating pressure at a distal end of a fluid line, the method comprising: 
       providing a fluid flow control system, the fluid flow control system having at least one liquid volume in valved communication with the distal end, a control volume in pressure communication with the liquid volume, a pressure transducer in communication with the control volume, and a pressure adjuster in communication with the control volume;  
       calibrating the pressure transducer;  
       establishing communication between the liquid volume and the distal end;  
       measuring a pressure of the control volume; and  
       adjusting the pressure in the control volume in accordance with the measured pressure.  
     
     
       17. A method according to  claim 16 , wherein calibrating the pressure transducer comprises: 
       isolating the liquid volume from the distal end;  
       measuring a first calibration pressure of the control volume;  
       pressurizing the liquid volume; and  
       measuring a second calibration pressure of the control volume.  
     
     
       18. A method according to  claim 16 , wherein calibrating the pressure transducer comprises: 
       isolating the liquid volume from the distal end;  
       measuring the pressure of the control volume;  
       positively pressurizing the liquid volume;  
       measuring the pressure of the control volume while the liquid volume is positively pressurized;  
       negatively pressurizing the liquid volume; and  
       measuring the pressure of the control volume while the liquid volume is negatively pressurized.  
     
     
       19. A method according to  claim 16 , wherein the liquid volume includes a flexible membrane that separates the liquid volume from the control volume. 
     
     
       20. A method according to  claim 16 , wherein the fluid flow control system includes a pump. 
     
     
       21. A method for regulating pressure in a fluid line, the method comprising: 
       providing a fluid flow control system, the fluid flow control system having a pressure transducer, a first liquid volume and a second liquid volume, the first liquid volume in valved communication with the second liquid volume;  
       establishing valved communication between a distal end of the fluid line and the first liquid volume and the second liquid volume;  
       calibrating the pressure transducer;  
       establishing communication between the first liquid volume and the distal end;  
       measuring a pressure of a fluid in pressure equilibrium with liquid in the first liquid volume;  
       adjusting the pressure in accordance with the measured pressure.  
     
     
       22. A method according to  claim 21 , wherein calibrating the pressure transducer comprises: 
       isolating the liquid volumes from the distal end;  
       measuring a first calibration pressure of the fluid in pressure equilibrium with liquid in the first liquid volume and a first calibration pressure of a fluid in pressure equilibrium with liquid in the second liquid volume;  
       pressurizing the first liquid volume;  
       measuring a second calibration pressure of the fluid in pressure equilibrium with liquid in the second liquid volume; and  
       adjusting the pressure in accordance with the measured pressures.  
     
     
       23. A method according to  claim 21 , wherein calibrating the pressure transducer comprises: 
       isolating the liquid volumes from the distal end;  
       measuring a first calibration pressure of the fluid in pressure equilibrium with liquid in the first liquid volume and a first calibration pressure of a fluid in pressure equilibrium with liquid in the second liquid volume;  
       positively pressurizing the first liquid volume;  
       measuring a second calibration pressure of the fluid in pressure equilibrium with liquid in the second liquid volume while the first liquid volume is positively pressurized;  
       negatively pressurizing the first liquid volume;  
       measuring a third calibration pressure of the fluid in pressure equilibrium with liquid in the second liquid volume while the first liquid volume is negatively pressurized; and  
       adjusting the pressure in accordance with the measured pressures.  
     
     
       24. A method according to  claim 21 , wherein each of the first and second liquid volumes includes a flexible membrane that separates the liquid volume from a control volume, and wherein the pressure measurements are taken from the control volume. 
     
     
       25. A method according to  claim 21 , wherein the first and second liquid volumes are disposed within a cassette. 
     
     
       26. A method according to  claim 25 , wherein the fluid flow control system includes a pump.